[inetutils] [coreutils] Build hostname from inetutils instead of coreutils

[oech3]

Reasons:

1. GNU coreutils is removing hostname for a long time and most distribution provides it from inetutils. It would cause some confusing by lacking feature at GNU coreutils.
2. Update of coreutils is delaying by cygpath specific issue. But inetutils is latest currently.

But it seems this is not easy to do.